We don't sell Demeter over here & I hear them calling “Buy me, buy me”.

The custom officers will love me when I come back from LV!

There isn't really a firm definition of either EDP or EDT (not to mention such boundary-blurring designations as “esprit de parfum” and “parfum de toilette”), and there's some overlap in the concentration of essential oils, so it could be either. (One site says that EDP is 10-30% aromatics and EDT is 5-20%: another says it's 15 to 22 for EDP and 8 to 15 for EDT, so there clearly isn't much agreement in the field–that's a really wide range.)

My guess is that the concentration is right on the boundary dividing EDP and EDT (which is to say about 15 per cent perfume oils), that it's the same strength as their other scents, but that, since these are blended scents that leave the usual Demeter territory, they're marketing them as EDP to fit into the wider universe of commercial scents, most of which seem to be marketed as EDP. (And it's also worth keeping in mind that the difference only makes a real difference when the company is marketing both, because they'll be constructed differently: if they want to call the only strength of something an EDP or an EDT or whatever, they can really have any concentration of essential oils that they want. Clinique, after all, calls all their women's scents “perfume”, though they're priced like EDPs.)